HIGH-SPEED LIVING ANIONIC-POLYMERIZATION OF METHACRYLIC ESTERS WITH ALUMINUM PORPHYRIN INITIATORS - ORGANOALUMINUM COMPOUNDS AS LEWIS-ACID ACCELERATORS

The polymerization of methacrylic esters initiated with methylaluminum tetraphenylporphyrin (1, X = Me) proceeded dramatically rapidly at room temperature in the presence of sterically crowded organoaluminum compounds such as methylaluminum ortho-substituted diphenolates (3a-3g), bis(triphenylmethanolate) (4b), and triphenylaluminum, where undesired reaction between the growing species (enolatoaluminum porphyrin, 2) and the Lewis acids was sterically suppressed. Use of less hindered Lewis acids such as methylaluminum diphenolates having no ortho substituents (3h, 3i), bis(diphenylmethanolate) (4a), trimethylaluminum, and triisobutylaluminum for the polymerization of methyl methacrylate under similar conditions resulted in termination of chain growth. However, this unfavorable termination was avoidable when the polymerization temperature was lowered to -40-degrees-C.